In the world of well drilling and directional drilling for utilities, drill bits, reamers and sonde housings are regularly attached and detached from one another or from the drill stem. In the prior art, this occurs in one of three ways.
One way is to simply use threaded connections. Threaded connections have a tendency to vibrate loose and to break. These connections have to be tightened to a predetermined torque, so that the threaded connection is as strong as possible and so that the connection does not become loosened in the almost inevitable event that the drill stem is turned in reverse. One of the many problems with this system is that in the making of threads, a stress riser is produced which causes the threads to weaken and break. Also, the tightened connection is hard to loosen which makes them slow to work with and dangerous because the operators sometimes use the drill rigs in an unsafe manner.
A second way is to use threaded connections in conjunction with a hex collar, such that after the pieces are threaded together as close as they can be, the flats on each piece are lined up and then a hex collar is slid over both pieces, then bolted into place. This system, when it works, is safer than the thread system, but it has its drawbacks. One problem is that in order to align the flats of each piece the threads cannot be tightened to their full torque. This makes the threads weaker than they would be otherwise. Also, the hex collar is held in position by a bolt that sometimes either falls out or breaks, allowing the hex collar to slide off the joint, which allows the threads to tighten as the bore is being drilled. Once this is done, the same problems as with the common threaded connection described above occur.
The third system, such as U.S. Pat. No. 6,148,935, uses round box and pin ends to intercept each other. A common o-ring system is used to make the connection water tight. An additional feature on each piece is a notch and projection system. For this system to work the notch and projection are lined up and engaged. Then roll pins or dowel pins are driven into holes that are drilled into each piece. These pins rely on friction to hold them into place. This system makes for a stronger connection than the threaded connection but it still has its drawbacks. One problem is that driving the pins in and out is difficult in some of the tight areas that the workers have to operate in. Another problem is in the manufacture of the connection, it is costly to make the notch and projection line up with the tolerances that are required to keep all of the elements lined up. A similar system to this is shown in Patent application no. 20040226750, which shows a complicated system of slots, keys and roll pins to connect drilling apparatus together.
Other industries could also benefit from my invention. It has come to my attention that artillery shells are held together by such devices as this, as shown by U.S. Pat. No. 4,348,956. U.S. Pat. No. 5,957,226 uses a pin retained by a second pin and a spring to lock together two halves of a drilling assembly. U.S. Pat. No. 4,363,505 describes a coupling assembly of two conduits. In this invention screws hold the couplings together. Other conduit couplings are held together by threaded pin devices, U.S. Pat. No. 6,918,618.
The pipe laying industry can also benefit from my invention. Conduits or pipes are connected today using various systems, ranging from compression type o-rings to gluing to various mechanical restraints.
With my invention these connections can be made stronger and cheaper than the mechanical restraining systems in use today.